Assignment: Introduction of Epidemiology:
The three largest cities in New Zealand are Auckland, Wellington, and Christchurch. Assume that these are the only three cities in New Zealand. According to a population wide survey in each of the three cities, there were the following existing cases of prostate cancer at the beginning of 2012: Auckland (330) Wellington (270) and Christchurch (250). See the table below for the more information.
Table 1. Populations and prostate cancer cases in New Zealand on January 1, 2012
|
City
|
Total Population (Jan 1, 2012)
|
Male Population (Jan I, 2012)
|
Prostate Cancer Cases (12:00 AM, Jan 1, 2012)
|
|
Auckland
|
400,000
|
196,000
|
330
|
|
Wellington
|
370,000
|
188,700
|
270
|
|
Christchurch
|
340,000
|
170,000
|
250
|
During 2012, 60 of the prostate cancer cases in Auckland die, as well as 70 in Wellington and 50 in Christchurch. In addition, 90 new cases are diagnosed in Auckland, 80 in Wellington and 100 in Christchurch.
Table 2. Death and new cases of prostate cancer during the 2012 by the three cities in New Zealand
|
City
|
Deaths from Prostate Cancer as of Dec 31, 2012
|
New Cases of Prostate Cancer diagnosed between Jan 1, 2012 and Dec 31, 2012
|
|
Auckland
|
60
|
90
|
|
Wellington
|
70
|
80
|
|
Christchurch
|
50
|
100
|
Based on these data only, can we calculate the incidence rate of prostate cancer in each of the three cities during the year 2012? Explain your answer.
1. What is the ratio of men with prostate cancer in Auckland relative to Wellington?
2. What is the proportion (not percent) of men with prostate cancer in New Zealand that live in Wellington?
3. Based on these data only, can we say the proportion of men with prostate cancer in Auckland was greater than Christchurch? Explain your answer.
4. What proportion of the men in Auckland who had prostate cancer at the start of 2012 died during 2012?
5. Determine the ratio of men that died of the disease relative to those that were ill but alive at the end of 2012 for Wellington.
6. What was the incidence rate (per 100,000) of prostate cancer in Christchurch during 2012? The denominator of rate is the at-risk population (those men without the disease at the beginning of the time period).
7. What was the point prevalence of prostate cancer (per 100,000) at the end of 2012 in Auckland? The denominator of point prevalence is the living population at the point in time when prevalence is measured.